EP0368802B1 - Apparatus for measuring accelerations, especially components of the gravitation force when measuring angles - Google Patents

Apparatus for measuring accelerations, especially components of the gravitation force when measuring angles Download PDF

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Publication number
EP0368802B1
EP0368802B1 EP89810815A EP89810815A EP0368802B1 EP 0368802 B1 EP0368802 B1 EP 0368802B1 EP 89810815 A EP89810815 A EP 89810815A EP 89810815 A EP89810815 A EP 89810815A EP 0368802 B1 EP0368802 B1 EP 0368802B1
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EP
European Patent Office
Prior art keywords
casing
electrode plates
instrument according
deflection
instrument
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EP89810815A
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German (de)
French (fr)
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EP0368802A1 (en
Inventor
Siegfried Theodor Stauber
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Wyler AG
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Wyler AG
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G01P15/125—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by capacitive pick-up
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
    • G01D5/24—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance
    • G01D5/241—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance by relative movement of capacitor electrodes
    • G01D5/2417—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance by relative movement of capacitor electrodes by varying separation

Definitions

  • the invention relates to a device according to the preamble of patent claim 1.
  • a device of this type is known from DE-C-2 523 446. Its measuring principle is based on the measurement of the voltage changes caused by the change in capacitance of the two capacitors in the associated circuits.
  • a device for measuring displacements which has a deflection part between two electrode plates.
  • the two capacitors thus also formed are each in the resonant circuit of an RC oscillator.
  • the frequency changes occurring due to deflection due to a shift are converted into a measurement signal.
  • the invention has for its object to find a device of the type mentioned, the small dimensions and robust, compact design, in particular when transmitting the measurement signal over larger distances, an even higher measurement accuracy with greater resolution of the measured value display.
  • At least one reference oscillator is additionally provided, which is designed for a constant oscillation frequency.
  • the oscillators should preferably be selected so that their current consumption is less than 1 mA at a supply voltage of more than 2 V. This ensures that the operating current does not cause any significant temperature changes that could affect the measurement accuracy.
  • their frequency should preferably be less than 50 kHz and their switching time should be shorter than 500 nS, so that the charging times of the capacitors are relatively long.
  • the arrangement according to the invention of the electronic means of the RC oscillators and of the computer, with the exception of the active capacitors, on one side of the device on a printed circuit board which faces away from the other of the two electrode plates, and the electrical connection of the other electrode plate to the electronic means A wire, which is routed through the deflecting part without contact, contributes significantly to the compact design, robustness and increased measuring accuracy of the device. Dielectric interference is avoided in this way.
  • FIG. 1 shows the deflection part 1 connected to ground. Due to its arrangement between two electrode plates 2, 3, it forms a common component of two capacitors arranged parallel to one another. These capacitors are in the resonant circuit of RC oscillators 4, 5, so that their frequency f L , f R is determined by the size of their capacitance. This size changes as a result of acceleration forces which cause a change in position of the pendulum-like deflection part 1 relative to the electrode plates 2, 3. It is thus possible to digitally display the determined measured value in a display device 7 by means of a computational evaluation of the change in the frequencies f L , f R in a computer 6 and by suitable calibration.
  • the display device (display) 7 can be firmly connected to a part of the rigid housing 8 of the device 9 shown by way of example in FIG.
  • the device 9 can also be removed via a connecting line 10, e.g. display device 7 arranged in a central control room, for which the digital measured value transmission is particularly advantageous.
  • the preferred embodiments of the invention are therefore based on the object of finding constructive measures which influence errors, in particular due to temperature changes and eliminate loss capacities as completely as possible.
  • the changes which act directly on the oscillators 4, 5, for example in the temperature range from -60 ° C. to + 70 ° C., can be taken into account in the computer 6 by additionally having a frequency f K of at least one further RC oscillator which is independent of acceleration forces same specification.
  • a frequency f K of at least one further RC oscillator which is independent of acceleration forces same specification.
  • the deflection part 1 which is made from a thin metal plate 12 with a thickness of, for example, 0.08 mm, is in direct contact with the likewise metallic housing 8 by being soldered to it. and it has the same coefficient of thermal expansion £ M as the housing, or both are made of the same material, for example brass.
  • this gap width is smaller in a ratio of £ E - £ M: £ M than that caused by the insulating spacers 16 , 17 formed distance, or their thickness, where £ E corresponds to the thermal expansion coefficient of the spacer bodies 16, 17 and £ M that of the housing 8, or, based on a predetermined width of the column 14, 15, the thickness of the spacer bodies 16, 17 calculated according to this ratio.
  • the housing 8 has two parts 18, 19 with mutually parallel inner surfaces 20, 21 to which the flat spacer bodies carrying the electrode plates 2, 3 are glued, and an annular outer edge 22 of the deflection part 1 is between the End faces parallel to one another are enclosed by shell regions 23, 24 projecting from one another and facing one another in the shape of a shell edge and projecting against the inner surfaces of the housing 20, 21.
  • the deflecting part 1 receives the firm metallic connection with the housing parts 18, 19 through radial extensions 25 of its outer edge 22, in that they protrude into a circumferential groove 26 between the housing parts 18, 19 and there, through this groove 26, non-illustrated solder metal with both housing parts 18, 19 are soldered.
  • At least three at least approximately axially parallel bores 27 are provided on the circumference of one of the end faces of the housing areas 18, 19, into which guide pins are inserted, so that when the deflecting part 1 is placed on this end face, they bear against the circular outer edge 22 of the deflecting part 1 and guide it.
  • the precise central arrangement of the circular electrode plates 2, 3, which is also required for reasons of measurement accuracy, relative to the aforementioned circular inner surfaces of the housing areas 23, 24 and relative to the deflection part can be achieved in various ways.
  • the electrode plates themselves are centered by means of these circular inner surfaces, in that they initially have a diameter that comes close to them and, after being glued to the spacer body 16, 17, are machined to the required diameter using a cutting tool.
  • the electrode plates a centrally formed, for example hollow cylindrical extension 29,30 ', which fits into a central opening 30 of the adjacent spacer. As shown in FIG. 5, the latter has a projecting hub part 31, which is centered in a central bore 32 of a housing wall having one of the inner surfaces 20, 21.
  • the spacers 16, 17 preferably include larger cavities 33, so that they only support the electrode plates 2, 3 in the manner of supporting ribs on the housing inner surfaces 20, 21.
  • a suitable spoke wheel-like embodiment is shown in FIG.
  • the central opening 30 in the hub-like central part 60 of the spacer body serves 16 or 17 of the passage of this wire and the centrally formed extension 29,30 'of the electrode plates 2,3.
  • central electrical connection through central openings 37, 38, 39 in the electrode plates 2, 3 and the deflecting part 1 also makes a significant contribution to avoiding the effect of external capacitances, in that an outside of the capacitors 4, 5 or the electrode plates 2, 3 and the deflecting part 1 passed electrical connecting wire would form an external capacity.
  • this central electrical connection considerably simplifies an embodiment of the device in which a metallic hood 40, which is in mass contact with the metallic housing 8, shields the electronic means 35 against electrical interference fields.
  • the one-sided arrangement of the electronic means 35 on One of the housing parts 18 also has the advantage that the opposite side of the housing 8 remains free of such means and can therefore have a solid molded reference block 42 or 43 on which one (FIG. 2) or more (FIG. 5 ) Reference surfaces 44; 45,46 for the angle measurement.
  • Fastening means for example screw holes 47-50, can also be provided on the reference block 42 or 43 in order to fasten the device in a stationary manner to a body to be monitored with regard to its angular position or deformation, such as, for example, components of high-rise buildings, manufacturing plants, ships, etc.
  • Fig. 5 shows an embodiment of a reference block 43, which has two correspondingly arranged electrode plates 3 ', 3 ⁇ of two devices according to the invention, not shown, for the angle measurement in two mutually perpendicular planes.
  • the deflection part 1 is held between two end faces by housing regions 23, 24 of two housing parts 18, 19.
  • the outer surfaces 52, 53 each form one of these end surfaces.
  • the measuring accuracy is further increased by a particularly easily resiliently deflectable configuration of the deflecting part 1, in that its circular part forming the active inner region 13 is formed by at least three bands 55-57 surrounding it in the form of an Archimedean spiral of more than 360 ° with its between the Housing parts 18,19 attached outer edge 22 is connected.
  • These spiral strips are produced in one piece with the deflecting part 1, for example by incorporating a number of correspondingly extending spiral separating lines in the photo-etching technique customary for the production of electrical conductor tracks.

Description

Die Erfindung betrifft ein Gerät gemäss dem Oberbegriff des Patentanspruchs 1.The invention relates to a device according to the preamble of patent claim 1.

Ein Gerät dieser Art ist bekannt durch die DE-C-2 523 446. Sein Messprinzip beruht auf der Messung der durch die Kapazitätsänderung der beiden Kondensatoren in den zugehörigen Stromkreisen verursachten Spannungsänderungen.A device of this type is known from DE-C-2 523 446. Its measuring principle is based on the measurement of the voltage changes caused by the change in capacitance of the two capacitors in the associated circuits.

Durch die DE-A-2 942 372 ist weiterhin ein Gerät zur Messung von Verschiebungen bekannt, das zwischen zwei Elektrodenplatten ein Auslenkteil aufweist. Die somit ebenfalls gebildeten beiden Kondensatoren befinden sich jeweils im Schwingkreis eines RC-Oszillators. Die durch Auslenkung aufgrund einer Verschiebung auftretenden Frequenzänderungen werden in ein Messignal umgerechnet.From DE-A-2 942 372 a device for measuring displacements is also known which has a deflection part between two electrode plates. The two capacitors thus also formed are each in the resonant circuit of an RC oscillator. The frequency changes occurring due to deflection due to a shift are converted into a measurement signal.

Der Erfindung liegt die Aufgabe zugrunde, ein Gerät der eingangs genannten Art zu finden, das bei kleinen Abmessungen und robuster, kompakter Bauweise, insbesondere auch bei der Uebertragung des Messsignals über grössere Abstände, eine noch höhere Messgenauigkeit bei grösserem Auflösungsvermögen der Messwertanzeige aufweist.The invention has for its object to find a device of the type mentioned, the small dimensions and robust, compact design, in particular when transmitting the measurement signal over larger distances, an even higher measurement accuracy with greater resolution of the measured value display.

Die Lösung dieser Aufgabe erfolgt erfindungsgemäss aufgrund der Merkmale des kennzeichnenden Teils des Patentanspruchs 1.This object is achieved according to the invention on the basis of the features of the characterizing part of patent claim 1.

Für eine rechnerische Kompensation von auf die Oszillatoren einwirkender Störeinflüsse, wie z.B. aufgrund von Temperaturänderungen, ist zusätzlich mindestens ein Referenzoszillator vorgesehen, der für eine konstante Schwingungsfrequenz ausgelegt ist.For computational compensation of disturbing influences acting on the oscillators, e.g. due to temperature changes, at least one reference oscillator is additionally provided, which is designed for a constant oscillation frequency.

Die Oszillatoren sind vorzugsweise so auszuwählen, dass ihre Stromaufnahme weniger als 1 mA bei einer Speisespannung von mehr als 2 V beträgt. Dadurch wird errreicht, dass durch den Betriebsstrom keine wesentlichen Temperaturveränderungen hervorgerufen werden, die die Messgenauigkeit beeinflussen könnten. Ausserdem soll ihre Frequenz vorzugsweise weniger als 50 kHz betragen und ihre Schaltzeit kürzer als 500 nS sein, so dass die Ladezeiten der Kondensatoren verhältnismässig lang sind.The oscillators should preferably be selected so that their current consumption is less than 1 mA at a supply voltage of more than 2 V. This ensures that the operating current does not cause any significant temperature changes that could affect the measurement accuracy. In addition, their frequency should preferably be less than 50 kHz and their switching time should be shorter than 500 nS, so that the charging times of the capacitors are relatively long.

Die erfindungsgemässe Anordnung der elektronischen Mittel der RC-Oszillatoren sowie des Rechners, mit Ausnahme der aktiven Kondensatoren, auf einer Seite des Gerätes an einer Leiterplatte, die der anderen der zwei Elektrodenplatten abgekehrt ist, und die elektrische Verbindung der anderen Elektrodenplatte mit den elektronischen Mitteln durch einen Draht, der kontaktlos zentral durch das Auslenkteil hindurchgeführt ist, tragen wesentlich zur kompakten Bauweise, Robustheit und erhöhten Messgenauigkeit des Gerätes bei. Dielektrische Störeinflüsse werden auf diese Weise vermieden.The arrangement according to the invention of the electronic means of the RC oscillators and of the computer, with the exception of the active capacitors, on one side of the device on a printed circuit board which faces away from the other of the two electrode plates, and the electrical connection of the other electrode plate to the electronic means A wire, which is routed through the deflecting part without contact, contributes significantly to the compact design, robustness and increased measuring accuracy of the device. Dielectric interference is avoided in this way.

Weitere, die Messgenauigkeit erhöhende, Störeinflüsse verringernde und/oder die Herstellung des Gerätes vereinfachende Ausführungsformen des erfindungsgemässen Gerätes sind Gegenstand von abhängigen Patentansprüchen sowie der folgenden Beschreibung von Ausführungsbeispielen anhand der Zeichnungen zu entnehmen.Further embodiments of the device according to the invention which increase the measuring accuracy, reduce interference and / or simplify the manufacture of the device are the subject of dependent patent claims and the following description of exemplary embodiments with reference to the drawings.

Es zeigt:

  • Fig.1 ein Funktionsschema des Gerätes einschliesslich seiner elektronischen Mittel und einer Messanzeige,
  • Fig.2 einen Axialquerschnitt durch das Gerät,
  • Fig.3 eine Ansicht des Auslenkteiles des Gerätes nach Fig.2,
  • Fig.4 eine Ansicht eines isolierenden Distanzkörpers des Gerätes nach Fig.2 und
  • Fig.5 einen querschnitt eines Gehäuseblockes für zwei Geräte.
It shows:
  • 1 shows a functional diagram of the device including its electronic means and a measurement display,
  • 2 shows an axial cross section through the device,
  • 3 shows a view of the deflection part of the device according to FIG. 2,
  • 4 shows a view of an insulating spacer body of the device according to FIG. 2 and
  • 5 shows a cross section of a housing block for two devices.

Die schematische Darstellung der Fig.1 zeigt das an Masse angeschlossene Auslenkteil 1. Es bildet durch seine Anordnung zwischen zwei Elektrodenplatten 2,3 gemeinsamen Bestandteil von zwei parallel nebeneinander angeordneten Kondensatoren. Diese Kondensatoren befinden sich im Schwingkreis von RC-Oszillatoren 4,5, so dass deren Frequenz fL,fR durch die Grösse ihrer Kapazität bestimmt ist. Diese Grösse ändert sich infolge von Beschleunigungskräften, die eine Positionsänderung des pendelartig wirkenden Auslenkteiles 1 relativ zu den Elektrodenplatten 2,3 bewirken. Somit ist es möglich, durch eine rechnerische Auswertung der Aenderung der Frequenzen fL,fR in einem Rechner 6 und durch geeignete Eichung den ermittelten Messwert in einem Anzeigegerät 7 digital angezeigt zu erhalten.The schematic representation of FIG. 1 shows the deflection part 1 connected to ground. Due to its arrangement between two electrode plates 2, 3, it forms a common component of two capacitors arranged parallel to one another. These capacitors are in the resonant circuit of RC oscillators 4, 5, so that their frequency f L , f R is determined by the size of their capacitance. This size changes as a result of acceleration forces which cause a change in position of the pendulum-like deflection part 1 relative to the electrode plates 2, 3. It is thus possible to digitally display the determined measured value in a display device 7 by means of a computational evaluation of the change in the frequencies f L , f R in a computer 6 and by suitable calibration.

Entsprechend dem Anwendungszweck kann das Anzeigegerät (Display) 7 mit einem Teil des starren Gehäuse 8 des in Fig.2 beispielhaft dargestellten Gerätes 9 fest verbunden sein. Das Gerät 9 kann jedoch auch über eine Verbindungsleitung 10 mit einem entfernt, z.B. in einem zentralen Kontrollraum angeordneten Anzeigegerät 7 verbunden sein, wofür die digitale Messwertübertragung besonders vorteilhaft ist.Depending on the application, the display device (display) 7 can be firmly connected to a part of the rigid housing 8 of the device 9 shown by way of example in FIG. However, the device 9 can also be removed via a connecting line 10, e.g. display device 7 arranged in a central control room, for which the digital measured value transmission is particularly advantageous.

Die hohe Genauigkeit, die durch die digitale Auswertung der Frequenzänderungen der RC-Oszillatoren möglich ist, führt jedoch nur zu entsprechend hoher Messgenauigkeit, wenn Fehleinflüsse weitgehend vermieden werden. Den bevorzugten Ausführungsformen der Erfindung liegt deshalb die Aufgabe zugrunde, konstruktive Massnahmen zu finden, die Fehleinflüsse, insbesondere aufgrund von Temperaturänderungen und Verlustkapazitäten, möglichst vollständig beseitigen.However, the high accuracy that is possible through the digital evaluation of the frequency changes of the RC oscillators only leads to a correspondingly high measurement accuracy if false influences are largely avoided. The preferred embodiments of the invention are therefore based on the object of finding constructive measures which influence errors, in particular due to temperature changes and eliminate loss capacities as completely as possible.

Die unmittelbar auf die Oszillatoren 4,5 wirkenden Veränderungen z.B. im Temperaturbereich von -60°C bis +70°C, lassen sich im Rechner 6 berücksichtigen, indem dieser zusätzlich eine von Beschleunigungskräften unabhängige Frequenz fK von mindestens einem weiteren RC-Oszillator mit sonst gleicher Spezifikation erhält. Auf diese Weise lassen sich durch allgemeine Einflüsse, z.B. Temperaturveränderungen bedingte Frequenzänderungen der RC-Oszillatoren 4,5 von den Frequenzänderungen unterscheiden, die durch die für die Messung wesentliche Positionsänderung des Auslenkteiles 1 zwischen den Elektrodenplatten 2,3 hervorgerufen worden ist.The changes which act directly on the oscillators 4, 5, for example in the temperature range from -60 ° C. to + 70 ° C., can be taken into account in the computer 6 by additionally having a frequency f K of at least one further RC oscillator which is independent of acceleration forces same specification. In this way, general changes, for example temperature changes, in frequency changes of the RC oscillators 4, 5 can be distinguished from the frequency changes which have been caused by the change in position of the deflection part 1 between the electrode plates 2, 3 which is essential for the measurement.

Zur Verringerung eines Temperatureinflusses auf das Schwingverhalten der RC-Oszillatoren 4,5 steht das aus einer dünnen Metallplatte 12 mit einer Dicke von z.B. 0,08 mm hergestellte Auslenkteil 1 in direktem Kontakt mit dem ebenfalls metallischen Gehäuse 8, indem es mit diesem verlötet ist, und es hat denselben thermischen Ausdehnungskoeffizienten £M wie das Gehäuse, oder beide bestehen aus demselben Material, z.B. Messing.To reduce the influence of temperature on the vibration behavior of the RC oscillators 4, 5, the deflection part 1, which is made from a thin metal plate 12 with a thickness of, for example, 0.08 mm, is in direct contact with the likewise metallic housing 8 by being soldered to it. and it has the same coefficient of thermal expansion £ M as the housing, or both are made of the same material, for example brass.

Um weiterhin zu verhindern, dass sich die Breite der Spalte 14, 15 zwischen dem Auslenkteil 1 und den Elektrodenplatten 2,3 bei Temperaturänderung verändert, ist diese Spaltbreite im Verhältnis von £E-£M : £M kleiner als die durch die isolierenden Distanzkörper 16,17 gebildete Distanz, bzw. deren Dicke, wobei £E dem thermischen Ausdehnungskoeffizienten der Distanzkörper 16,17 und £M demjenigen des Gehäuses 8 entspricht, bzw. wird ausgehend von einer vorgegebenen Breite der Spalte 14,15 die Dicke der Distanzkörper 16,17 nach diesem Verhältnis berechnet. Dabei hat das Gehäuse 8 zwei Teile 18,19 mit zueinander parallelen Innenflächen 20,21, an denen die die Elektrodenplatten 2,3 tragenden ebenen Distanzkörper angeklebt sind, und ein kreisringförmiger Aussenrand 22 des Auslenkteiles 1 ist zwischen den zueinander parallelen Stirnflächen von schalenrandförmig über die Gehäuseinnenflächen 20,21 überstehenden und gegeneinandergerichteten Gehäusebereichen 23,24 eingeschlossen.In order to further prevent the width of the gaps 14, 15 between the deflection part 1 and the electrode plates 2, 3 from changing as the temperature changes, this gap width is smaller in a ratio of £ E - £ M: £ M than that caused by the insulating spacers 16 , 17 formed distance, or their thickness, where £ E corresponds to the thermal expansion coefficient of the spacer bodies 16, 17 and £ M that of the housing 8, or, based on a predetermined width of the column 14, 15, the thickness of the spacer bodies 16, 17 calculated according to this ratio. The housing 8 has two parts 18, 19 with mutually parallel inner surfaces 20, 21 to which the flat spacer bodies carrying the electrode plates 2, 3 are glued, and an annular outer edge 22 of the deflection part 1 is between the End faces parallel to one another are enclosed by shell regions 23, 24 projecting from one another and facing one another in the shape of a shell edge and projecting against the inner surfaces of the housing 20, 21.

Die feste metallische Verbindung mit den Gehäuseteilen 18, 19 erhält das Auslenkteil 1 durch radiale Fortsätze 25 seines Aussenrandes 22, indem diese in eine Umfangsrille 26 zwischen den Gehäuseteilen 18,19 hineinragen und dort durch diese Rille 26 ausfüllendes, nichtdargestelltes Lötmetall mit beiden Gehäuseteilen 18,19 verlötet sind.The deflecting part 1 receives the firm metallic connection with the housing parts 18, 19 through radial extensions 25 of its outer edge 22, in that they protrude into a circumferential groove 26 between the housing parts 18, 19 and there, through this groove 26, non-illustrated solder metal with both housing parts 18, 19 are soldered.

Um die genau zentrische Montage des kreisrunden Auslenkteiles 1 relativ zu den kreisrunden Innenflächen der Gehäusebereiche 23, 24 zu erleichtern, sind am Umfang einer der genannten Stirnflächen der Gehäusebereiche 18,19 mindestens drei zumindest angenähert achsparallel gerichtete Bohrungen 27 vorgesehen, in die Führungsstifte gesteckt werden, so dass sie beim Auflegen des Auslenkteiles 1 auf diese Stirnfläche an dem kreisrunden Aussenrand 22 des Auslenkteiles 1 anliegen und ihn führen. Nach dem Fixieren des Auslenkteiles 1 an dem Gehäuseteil 18, z.B. durch stellenweises Anlöten, können diese nichtdargestellten Führungsstifte wieder entfernt werden.In order to facilitate the precisely central assembly of the circular deflection part 1 relative to the circular inner surfaces of the housing areas 23, 24, at least three at least approximately axially parallel bores 27 are provided on the circumference of one of the end faces of the housing areas 18, 19, into which guide pins are inserted, so that when the deflecting part 1 is placed on this end face, they bear against the circular outer edge 22 of the deflecting part 1 and guide it. After fixing the deflection part 1 to the housing part 18, e.g. by soldering in places, these guide pins (not shown) can be removed again.

Die aus Gründen der Messgenauigkeit ebenfalls erforderliche, genaue zentrische Anordnung der kreisrunden Elektrodenplatten 2,3 relativ zu den genannten kreisrunden Innenflächen der Gehäusebereiche 23,24 und relativ zu dem Auslenkteil kann auf verschiedene Weise erreicht werden. Beispielsweise werden die Elektrodenplatten durch diese kreisrunden Innenflächen selbst zentriert, indem sie vorerst einen an diese heranreichenden Durchmesser aufweisen und nach der Verklebung mit dem Distanzkörper 16,17 mittels eines Schneidwerkzeuges auf den erforderlichen Durchmesser bearbeitet werden.The precise central arrangement of the circular electrode plates 2, 3, which is also required for reasons of measurement accuracy, relative to the aforementioned circular inner surfaces of the housing areas 23, 24 and relative to the deflection part can be achieved in various ways. For example, the electrode plates themselves are centered by means of these circular inner surfaces, in that they initially have a diameter that comes close to them and, after being glued to the spacer body 16, 17, are machined to the required diameter using a cutting tool.

Bei einer bevorzugten Ausführungsform haben die Elektrodenplatten einen zentrisch angeformten, beispielsweise hohlzylindrischen Fortsatz 29,30′, der in eine zentrale Oeffnung 30 des angrenzenden Distanzkörpers passt. Letzterer hat entsprechend der Darstellung in Fig.5 einen abstehenden Nabenteil 31, der in einer zentralen Bohrung 32 einer eine der Innenflächen 20,21 aufweisenden Gehäusewand zentriert ist.In a preferred embodiment, the electrode plates a centrally formed, for example hollow cylindrical extension 29,30 ', which fits into a central opening 30 of the adjacent spacer. As shown in FIG. 5, the latter has a projecting hub part 31, which is centered in a central bore 32 of a housing wall having one of the inner surfaces 20, 21.

Für eine verbesserte Isolierung gegenüber Fremd-oder Verlustkapazitäten schliessen die Distanzkörper 16,17 vorzugsweise grössere Hohlräume 33 ein, so dass sie die Elektrodenplatten 2,3 nur tragrippenartig an den Gehäuseinnenflächen 20,21 abstützen. Eine geeignete speichenradartige Ausführungsform ist in Fig.4 dargestellt.For improved insulation against external or loss capacities, the spacers 16, 17 preferably include larger cavities 33, so that they only support the electrode plates 2, 3 in the manner of supporting ribs on the housing inner surfaces 20, 21. A suitable spoke wheel-like embodiment is shown in FIG.

Bei einer bevorzugten Ausführungsform des Gerätes, bei der die elektronischen Mittel 35 an nur einem Gehäuseteil 18 angebracht sind und die elektrische Verbindung der Elektrodenplatten 2,3 mit diesen durch einen zentralen Draht 34 erfolgt, dient die zentrale Oeffnung 30 in dem nabenartigen Zentralteil 60 des Distanzkörpers 16 oder 17 der Hindurchführung diese Drahtes sowie des zentrisch angeformten Fortsatzes 29,30′ der Elektrodenplatten 2,3.In a preferred embodiment of the device, in which the electronic means 35 are attached to only one housing part 18 and the electrical connection of the electrode plates 2, 3 to them takes place by means of a central wire 34, the central opening 30 in the hub-like central part 60 of the spacer body serves 16 or 17 of the passage of this wire and the centrally formed extension 29,30 'of the electrode plates 2,3.

Die zentrale elektrische Verbindung durch zentrale Oeffnungen 37,38,39 in den Elektrodenplatten 2,3 und dem Auslenkteil 1 trägt ebenfalls wesentlich zur Vermeidung der Einwirkung von Fremdkapazitäten bei, indem ein aussen an den Kondensatoren 4,5 bzw. den Elektrodenplatten 2,3 und dem Auslenkteil 1 vorbeigeführter elektrischer Verbindungsdraht eine Fremdkapazität bilden würde. Ausserdem wird durch diese zentrale elektrische Verbindung eine Ausführungsform des Gerätes wesentlich erleichtert, bei der eine in Massenkontakt mit dem metallischen Gehäuse 8 stehende metallische Haube 40 die elektronischen Mittel 35 gegen elektrische Störfelder abschirmt.The central electrical connection through central openings 37, 38, 39 in the electrode plates 2, 3 and the deflecting part 1 also makes a significant contribution to avoiding the effect of external capacitances, in that an outside of the capacitors 4, 5 or the electrode plates 2, 3 and the deflecting part 1 passed electrical connecting wire would form an external capacity. In addition, this central electrical connection considerably simplifies an embodiment of the device in which a metallic hood 40, which is in mass contact with the metallic housing 8, shields the electronic means 35 against electrical interference fields.

Die einseitige Anordnung der elektronischen Mittel 35 an einem der Gehäuseteile 18 hat auch den Vorteil, dass die gegenüberliegende Seite des Gehäuses 8 frei von solchen Mitteln bleibt und somit einen massiv angeformten Referenzblock 42, bzw. 43 aufweisen kann, an dem sich eine (Fig.2) oder mehrere (Fig.5) Referenzflächen 44;45,46 für die Winkelmessung befinden. An dem Referenzblock 42 oder 43 können auch Befestigungsmittel, z.B. Schraubenlöcher 47-50 vorgesehen sein, um das Gerät stationär an einem hinsichtlich seiner Winkelposition oder Verformung zu überwachenden Körper, wie z.B. Bauelementen von Hochhäusern, Fabrikationsanlagen, Schiffen u.s.w., zu befestigen.The one-sided arrangement of the electronic means 35 on One of the housing parts 18 also has the advantage that the opposite side of the housing 8 remains free of such means and can therefore have a solid molded reference block 42 or 43 on which one (FIG. 2) or more (FIG. 5 ) Reference surfaces 44; 45,46 for the angle measurement. Fastening means, for example screw holes 47-50, can also be provided on the reference block 42 or 43 in order to fasten the device in a stationary manner to a body to be monitored with regard to its angular position or deformation, such as, for example, components of high-rise buildings, manufacturing plants, ships, etc.

Fig. 5 zeigt ein Ausführungsbeispiel eines Referenzblockes 43, der für die Winkelmessung in zwei zueinander senkrechten Ebenen zwei entsprechend zueinander angeordnete Elektrodenplatten 3′,3˝ von zwei nicht vollständig dargestellten erfindungsgemässen Geräten aufweist. Wie mit Bezug auf das Ausführungsbeispiel nach Fig.2 zuvor beschrieben, wird das Auslenkteil 1 zwischen zwei Stirnflächen von Gehäusebereichen 23,24 zweier Gehäuseteile 18, 19 gehalten. Beim Ausführungsbeispiel nach Fig. 5 bilden die Aussenflächen 52,53 jeweils eine dieser Stirnflächen.Fig. 5 shows an embodiment of a reference block 43, which has two correspondingly arranged electrode plates 3 ', 3˝ of two devices according to the invention, not shown, for the angle measurement in two mutually perpendicular planes. As described above with reference to the exemplary embodiment according to FIG. 2, the deflection part 1 is held between two end faces by housing regions 23, 24 of two housing parts 18, 19. In the exemplary embodiment according to FIG. 5, the outer surfaces 52, 53 each form one of these end surfaces.

Die Messgenauigkeit wird weiterhin durch eine besonders leicht federnd auslenkbare Ausgestaltung des Auslenkteiles 1 erhöht, indem dessen kreisförmiger, den aktiven inneren Bereich 13 bildender Teil durch mindestens drei in Form einer archimedischen Spirale von mehr als 360° ihn umgebende Bänder 55-57 mit seinem zwischen den Gehäuseteilen 18,19 befestigten Aussenrand 22 verbunden ist. Die Herstellung dieser Spiralbänder erfolgt in einem Stück mit dem Auslenkteil 1, indem beispielsweise in der für die Herstellung von elektrischen Leiterbahnen üblichen Fotoätztechnik mehrere entsprechend verlaufende spiralförmige Trennlinien eingearbeitet werden.The measuring accuracy is further increased by a particularly easily resiliently deflectable configuration of the deflecting part 1, in that its circular part forming the active inner region 13 is formed by at least three bands 55-57 surrounding it in the form of an Archimedean spiral of more than 360 ° with its between the Housing parts 18,19 attached outer edge 22 is connected. These spiral strips are produced in one piece with the deflecting part 1, for example by incorporating a number of correspondingly extending spiral separating lines in the photo-etching technique customary for the production of electrical conductor tracks.

Claims (11)

1.Instrument or measuring accelarations, particularly of gravitation components for goniometry based on the deflection of a circular, metallic deflection part (1,13) which, for forming two adjacent capacitors is held in spring-elastic, membrane-like, spaced manner between two electrode plates (2,3) and between two parts (18,19) of a casing (8) surrounding the electrode plates (2,3) and the deflection part (1,13), characterized in that the capacitors are in each case arranged in the oscillating circuit of a RC-oscillator (4,5), the RC-oscillators are connected to a digital computer, which converts the frequency changes caused by the deflection into a measuring signal, the electrical means (35) of the RC-oscillators (4,5) and of the computer are located on one side of the instrument which, with respect to one of said electrode plates (2) is positioned averted from the other electrode plate (3) and an electrical connecting wire (34) is passed in contact-free manner through a central hole (39) in the circular deflection part (1,13) and in the electrode plate (2) adjacent to the electrical means (35) connecting the electrode plate (3) more remote from the electronic means (35) to the latter.
2. Instrument according to claim 1, characterized in that the electrode plates (2,3) adjacent to their central hole (37,38) and at right angles thereto, have at least one electrically conducting extension (29,30′) which, together with the electrical connecting wire (34) extends through an opening (28,41) in the adjacent casing part (18,19) up to the outside thereof, where both are soldered together.
3. Instrument according to claim 1 or 3, characterized in that the common casing (8) surrounding the electrode plates (2,3) and the deflection part (1,13) is metallic, the electrode plates (2,3) are insulated by an insulating spacer (16,17) from the metallic casing (8) and in the case of non-deflected deflecting part (1,13) the spacing (14,15) between the electrode plate (2,3) and the deflection part (1,13) is constant, even after temperature chages, in that its size forms the ratio £E-£M : £M to the size of the distance formed by the insulating spacers, £E corresponding to the thermal expansion coefficient of the insulating material of the spacer (16,17) and £M to that of the metallic casing (8).
4. Instrument according to claim 3, characterized in that the insulating spacers (16,17) have recesses (33) or cavities.
5. Instrument according to claim 4, characterized in that the insulating spacers (16,17) are shaped like a spoked wheel with at least three spokes (fig.4).
6. Instrument according to claim 2, characterized in that the electrically conductive extension (29,30′) of at least one of the electrode plates (2,3) is shaped in tubular manner thereon, surrounds the electrical connecting wire (34) and is surrounded by the hub (60) of the spoked wheel-like spacer (16,17), so that it centres the same.
7. Instrument according to one of claims 1 to 6, characterized in that, the deflection part (13) is spirally surrounded by at least three bands (55-57) in an angular range of more than 360° and said bands connected to a circular outer rim (22), which is fixed between the two casing parts (18,19), the deflection part (13), the bands (55-57) and the outer rim (22) being shaped from a common metal foil, so that they also extend in the same plane.
8. Instrument according to claim 7, characterized in that the circular outer im (22) surrounding the deflection part (13) is held between circular, planar rims (23,24) of the two casing parts (18,19) so as to engage on the same and projections (25) projecting radially from the outer rim (22) project into a circumferential groove (26) formed between the casing parts (18,19), the latter being formed from the same matallic material or a material with the same thermal expansion coefficient as the deflection part (13) and the extensions (25) are soldered to the casing parts (18,19) within said circumferential groove.
9. Instrument according to one of claims 1 to 8, characterized in that at least one further RC-oscillator (11) is provided for computational temperature compensation and which, as a reference oscillator, has a constant oscillating frequency.
10. Instrument according to one of claims 1 to 9, characterized in that to the part (18) of a metallic instrument casing (8) forming the electrical grounding carrying the electronical means (35) is fixed with electrical contact a metallic cover (40) surrounding said means, the other part (19) of the metallic casing (8) forming a casing block (42, 43), on which are provided fastening means (47-50) and/or a reference surface (44-46) for angular measurements.
11. Instrument according to claim 10, characterized in that the instrument is connected to a second one of the same type, one (3) of the two electrode plates (2,3) of one of the instruments and one (3′) of the electrode plates of the other instrument at an angle of 90° are,rigidly fixed to a common casing block (43).
EP89810815A 1988-11-07 1989-10-31 Apparatus for measuring accelerations, especially components of the gravitation force when measuring angles Expired - Lifetime EP0368802B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH4125/88A CH677540A5 (en) 1988-11-07 1988-11-07
CH4125/88 1988-11-07

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EP0368802A1 EP0368802A1 (en) 1990-05-16
EP0368802B1 true EP0368802B1 (en) 1992-08-05

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EP89810815A Expired - Lifetime EP0368802B1 (en) 1988-11-07 1989-10-31 Apparatus for measuring accelerations, especially components of the gravitation force when measuring angles

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US (1) US5022264A (en)
EP (1) EP0368802B1 (en)
JP (1) JPH02171660A (en)
CH (1) CH677540A5 (en)
DE (1) DE58901991D1 (en)
RU (1) RU1814732C (en)

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Publication number Priority date Publication date Assignee Title
JPH0682469A (en) * 1992-09-04 1994-03-22 Japan Aviation Electron Ind Ltd Accelerometer
DE4326666C1 (en) * 1993-08-09 1995-02-23 Wild Heerbrugg Ag Capacitive sensor
GB2378517B (en) * 2000-05-22 2003-08-06 Toyota Motor Co Ltd Sensing device and sensor apparatus
US6904805B2 (en) * 2003-06-03 2005-06-14 Cherry Corporation Accelerometer
US8177209B2 (en) * 2010-07-08 2012-05-15 Lai Lien Steel Co., Ltd. Vise with self-setting locking assembly having a spring actuated slide member for engaging a slide bar

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Publication number Priority date Publication date Assignee Title
US2767973A (en) * 1953-01-19 1956-10-23 Bendix Aviat Corp Accelerometers
CH588069A5 (en) * 1975-02-27 1977-05-31 Wyler Ag
JPS5562310A (en) * 1978-10-20 1980-05-10 Hiromi Ogasawara Direct-acting type displacement detector
CH642461A5 (en) * 1981-07-02 1984-04-13 Centre Electron Horloger ACCELEROMETER.
US4758821A (en) * 1983-12-28 1988-07-19 Timeback Systems, Inc. Methods and apparatus for analog-to-digital conversion
US4581676A (en) * 1984-09-17 1986-04-08 General Signal Corporation Electrical contact coating for silicon pressure transducers

Also Published As

Publication number Publication date
EP0368802A1 (en) 1990-05-16
DE58901991D1 (en) 1992-09-10
US5022264A (en) 1991-06-11
JPH02171660A (en) 1990-07-03
RU1814732C (en) 1993-05-07
CH677540A5 (en) 1991-05-31

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